314,612 views
19 votes
19 votes
If x-y=9 and xy=2,find the value of (x square + y square)

User Pedro Alves
by
2.7k points

1 Answer

12 votes
12 votes

Answer:

x² + y² = 85

Explanation:

Using the expansion

(x - y)² = x² + y² - 2xy , then

x² + y² - 2xy = (x - y)² ( add 2xy to both sides )

x² + y² = (x - y)² + 2xy ← substitute given values

= 9² + 2(2)

= 81 + 4

= 85

User Myx
by
2.7k points
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